JP3094752B2 - Vehicle suspension control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suspension control device for a vehicle, and more particularly to a suspension control device for a vehicle which is suitable for achieving a balance between steering stability and riding comfort.

[0002]

2. Description of the Related Art Conventionally, a vehicle equipped with a suspension control device has an anti-nose dive control for suppressing a nose dive phenomenon in which a front portion of the vehicle lowers when the vehicle is braked. Anti-squat control to suppress the squat phenomenon that the front part of the vehicle rises, anti-roll control to suppress the rolling (rolling) phenomenon at the time of cornering of the vehicle, ride comfort control to improve the ride comfort when the vehicle is traveling on rough roads, Functions such as high-speed responsive control during high-speed running of the vehicle are provided. Among these various controls, as the anti-roll control, a control for increasing the damping force of the suspension mechanism when the steering angular velocity and the vehicle speed (or the engine speed) map exceed a threshold value during cornering of the vehicle has been developed. ing.

[0003]

However, in a vehicle equipped with the above-mentioned conventional suspension control device, a pitching (pitch) phenomenon acting on the vehicle is detected by a vertical acceleration sensor provided in the vehicle in advance. Although it has a function to perform suspension control, it does not have a function to detect the magnitude of rolling that acts on the vehicle due to disturbance such as a rut on the road on which the vehicle travels or crosswind, etc.
At the time of high-speed running of the vehicle, control was performed in which the damping force of the suspension mechanism was set high in advance in order to increase the steering stability, but due to the setting of the high damping force, ride comfort was somewhat sacrificed. There was a problem that had to be. That is, in the related art, there is a problem that it is difficult to achieve both steering stability and riding comfort regardless of whether the vehicle is running at high speed.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned disadvantages of the prior art. In particular, the present invention makes it possible to detect rolling (rolling) acting on a vehicle body due to disturbance such as a rut or a cross wind on a road surface on which a vehicle travels. An object of the present invention is to provide a vehicle suspension control device that achieves both steering stability and ride comfort by controlling the damping force of a suspension mechanism based on the magnitude.

[0005]

According to the present invention, there is provided a vehicle equipped with a suspension mechanism and a stabilizer, the stabilizer being attached to the stabilizer and detecting a twist on the right wheel side of the stabilizer; A second detecting means attached to the stabilizer for detecting a twist on the left wheel side of the stabilizer, and a positive and negative reference value relating to a difference between the twists detected by the first and second detecting means, respectively; A set of first threshold value groups and a set of first threshold values set corresponding to the respective reference values of the first threshold value group and each having a value greater than the set reference value; Storage means storing two threshold value groups, and a damping force of the suspension mechanism based on detection data of the first and second detection means and storage data of the storage means. And a Gosuru control means, first the control means, stored in the absolute value and the storage means of each detected difference twisted by the first and second detecting means
And a magnitude relation determining function for determining a magnitude relation between the absolute value of each reference value of the second threshold value group and an absolute value of the torsion difference, If the absolute value is less than the absolute value, the damping force of the suspension mechanism is set to a lower state, and the absolute value of the torsional difference is equal to or greater than the absolute value of any one of the reference values of the first threshold value group, and If the absolute value of any of the reference values of the second threshold group is less than the absolute value of the reference value, the damping force is set to a medium state, and the absolute value of the torsional difference is determined by any of the second threshold group. A damping force setting function for setting the damping force to a higher state when the absolute value is equal to or greater than the absolute value of the reference value.
The configuration is adopted. This aims to achieve the above-mentioned object.

[0006]

According to the present invention, the first detecting means detects a twist on the right wheel side of the stabilizer, the second detecting means detects a twist on the left wheel side of the stabilizer, and a difference between the detected twists. Is provided with a function for determining the magnitude relationship between the absolute value of the reference value and the absolute value of each of the reference values of the first and second threshold value groups. Since the degree of rolling acting on the vehicle due to a disturbance such as a cross wind can be ascertained, the damping force control of the suspension mechanism can be performed in accordance with the degree of rolling by utilizing this.
Further, the damping force of the suspension mechanism is adjusted according to the magnitude relationship between the absolute value of the difference between the torsion on the right wheel side and the left wheel side of the stabilizer and the absolute value of each reference value of the first and second threshold value groups. Since it has a function of appropriately setting low, medium, and high states, it does not have a function of detecting rolling that acts on the vehicle due to, for example, a rut or a cross wind on the road surface of the vehicle, as in the related art. In addition, it is not necessary to set a high damping force in advance at the expense of ride comfort in order to enhance the steering stability of the vehicle when traveling at high speeds. As a result, it is possible to improve ride comfort especially at high speeds. It becomes possible. Furthermore, in other words, the damping force can be set to an optimum state according to the degree of rolling caused by disturbance such as whether there is a rut on the vehicle traveling road surface or whether the cross wind is strong or weak. Regardless, it is possible to achieve both steering stability and ride comfort.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a vehicle suspension control apparatus according to an embodiment of the present invention;

First, the structure of a main part of a vehicle equipped with the vehicle suspension control device of the present embodiment will be described with reference to FIGS. 2 and 3. An oil damper 3, a coil spring and a coil spring are provided near the right front wheel of the vehicle 1. 4, a suspension mechanism 2 including an actuator 5 is provided, and a suspension mechanism 6 including an oil damper 7, a coil spring 8, and an actuator 9 is provided near the left front wheel. A suspension mechanism 10 including an oil damper 11, a coil spring 12, and an actuator 13 is provided near the right rear wheel, and an oil damper 15, a coil spring 16, and an actuator 17 are provided near the left rear wheel. A suspension mechanism 14 is provided.

Further, inside the vehicle 1, a steering sensor 18 for detecting a steering angle, a vertical acceleration sensor 19 for detecting a vertical acceleration acting on the vehicle body, a vehicle speed sensor 20 for detecting a vehicle speed, a vehicle driver A throttle sensor 21 for detecting a throttle opening degree based on an accelerator pedal depression operation, a brake switch 22 for detecting a brake operation state based on a vehicle driver's depression operation of a brake pedal, and an engine rotation speed signal. An ignition coil 23 and an electronic suspension controller 25 (hereinafter, abbreviated as a controller) for performing suspension control are provided.

Further, a stabilizer 2 is provided between both ends of a tie rod 26 connecting the right front wheel 1A side and the left front wheel 1B side.
7 is equipped. When the vehicle 1 is traveling, the stabilizer 27 does not operate as a spring when the right front wheel 1A and the left front wheel 1B move in the up-down direction, but the right front wheel 1A and the left front wheel 1B are turned upside down. When moving in a phase (when rolling occurs), torsion occurs near the center of the stabilizer 27, and the torsional rigidity serves as resistance to suppress the inclination of the vehicle body.

A gear 28 is fixed to the stabilizer 27 on the side closer to the right front wheel, and a gear 29 is fixed to the gear 28.
And a first potentiometer 31 is mounted on the gear 29 via a shaft 30. Similarly, a gear 32 is fixed to the left front wheel side of the stabilizer 27, a gear 33 is engaged with the gear 32, and a second potentiometer 35 is mounted on the gear 33 via a shaft 34. .

When the vehicle 1 travels, a rolling phenomenon occurs in the vehicle body due to the influence of a rut on a road surface on which the vehicle travels, a side wind, and the like, and the stabilizer 27 is twisted accordingly. The rotation of the gear 29 also causes the rotation of the gear 29, whereby the rotation of the gear 29 is transmitted to the first potentiometer 31 via the shaft 30. Similarly, the gear 32 is rotated by the torsion of the stabilizer 27, so that the gear 33 is also rotated, and accordingly, the rotation of the gear 33 is changed via the shaft 34 to the second potentiometer 35.
To be transmitted to

The first potentiometer 31 has a function as a torque sensor for detecting a torsional torque near the right front wheel of the stabilizer 27 via a gear 28 and a gear 29, and outputs a voltage signal corresponding to the detected torsional torque described later. The signal is output to the differential amplifier 47. The second potentiometer 35 has a function as a torque sensor for detecting the torsional torque of the stabilizer 27 near the left front wheel via the gears 32 and 33, and outputs a voltage signal corresponding to the detected torsional torque, as described later. Dynamic amplifier 47
Output to

Next, the configuration of the vehicle suspension control device of the present embodiment will be described with reference to FIG. 1. The controller 25 has a battery 38 via fuses 36 and 37.
And an ignition switch 40 via a fuse 39.
, A brake switch 22, a stop lamp 41 which lights up when the brake is operated, and an auto / sport switch 4.
2, the DN switch 43 and the ignition coil 23
, Noise filter 44, sport / auto lamp 4
5 are connected to each other.

The controller 25 includes a vehicle speed sensor 20, a steering sensor 18, a vertical acceleration sensor 19, a throttle sensor 21, an engine control controller (EPI controller) 46, and oil dampers 3, 7, and 11. , 15 are set to predetermined states (“hard state”, “soft state”, and “medium state”), respectively.

Further, a first potentiometer 31 and a second potentiometer 35 are connected to the controller 25 via a differential amplifier 47, respectively.
7 outputs to the controller 25 a signal corresponding to the potential difference between the voltage detected by the first potentiometer 31 and the voltage detected by the second potentiometer 35.

The controller 25 determines the steering operation state based on the output signal of the steering sensor 18, determines the degree of vertical acceleration acting on the vehicle body based on the output signal of the vertical acceleration sensor 19, and determines the output signal of the vehicle speed sensor 20. , The degree of the throttle opening is determined based on the output signal of the throttle sensor 21, and the operation state of the brake is determined based on the output signal of the brake switch 22.

The controller 25 includes a differential amplifier 4
7 (first and second potentiometers 31, 3)
5, the magnitude of the rolling (rolling) acting on the vehicle body is determined based on the potential difference between the detected voltages, and the operation of each of the actuators 5, 9, 13, 17 is controlled. The damping force of 11 and 15 is in a predetermined state ("soft state", "medium state", "hard state")
Is controlled so that This will be described later.

Here, the characteristic point of this embodiment will be described. As shown in FIG. 4, the output value of the differential amplifier 47 is a positive first threshold value centered on the voltage 0 [V]. A set of “first threshold group” having a (reference value) and a negative first threshold value (reference value), and are set corresponding to the respective reference values of the first threshold group. And a second threshold group having a set of second thresholds (reference values) in which the absolute value of each set reference value is greater than each reference value of the first threshold group. Is set. Data corresponding to the first and second threshold value groups is stored in a memory 4 built in the controller 25.
8 is stored in advance.

The controller 25 has a function of determining the magnitude relationship between the output of the differential amplifier 47 and the “first threshold group” and “second threshold group”. Is the "first threshold group"
When the positive and negative first threshold values are less than the absolute values (when the vehicle traveling road surface is flat and the crosswind is weak, for example), the operation of each of the actuators 5, 9, 13, and 17 is controlled to The damping forces of 3, 7, 11, and 15 are set to “soft state”.

The controller 25 includes a differential amplifier 4
7 is greater than or equal to the absolute values of the positive and negative first thresholds of the “first threshold group” and the positive and negative second thresholds of the “second threshold group” When the vehicle traveling road surface is relatively flat and the crosswind is moderate, the operation of each of the actuators 5, 9, 13, 17 is controlled so that the oil dampers 3, 7, 11, 15 is set to the “medium state”, and then the differential amplifier 47 is set.
When the absolute value of the output of the first threshold value falls below the absolute values of the positive and negative first threshold values of the “first threshold group”, the damping force is maintained in the “medium state” for 2 seconds, for example.
Switch to "soft state".

The controller 25 includes a differential amplifier 4
When the absolute value of the output of the second control unit 7 is equal to or greater than the absolute value of the second threshold value (positive or negative) of the “second threshold value group” (for example, when there is a rut on the road surface on which the vehicle is running and strong cross wind), ,
The operation of each of the oil dampers 3, 9, 13 and 17 is controlled by
The damping forces of 7, 11, and 15 are set to the “hard state”, and then the absolute value of the output of the differential amplifier 47 is changed to the absolute value of the positive and negative first thresholds of the “first threshold group”. When the value decreases to less than 2, the damping force is maintained in the "hard state" for, for example, 2 seconds, and then switched to the "soft state".

Next, an example of suspension control in the present embodiment configured as described above will be described with reference to FIG.

When the vehicle 1 is running, the stabilizer 2
7 is twisted, the first potentiometer 31
Detects the torsional torque of the stabilizer 27 via the gears 28 and 29, and outputs a voltage signal corresponding to the detected torsional torque to the differential amplifier 47. Further, the second potentiometer 35 detects the torsional torque of the stabilizer 27 via the gears 32 and 33, and outputs a voltage signal corresponding to the detected torsional torque to the differential amplifier 47. As a result, the differential amplifier 47 compares the potential difference between the output voltages of the first and second potentiometers 31 and 35 with the controller 25.
Output to

The controller 25 determines whether the absolute value of the output of the differential amplifier 47 is greater than or less than the absolute values of the positive and negative first thresholds of the “first threshold group” ( Step S1) If the absolute values of the positive and negative first thresholds of the “first threshold group” are less than the absolute value (the vehicle traveling road surface is flat and the crosswind is weak),
The operation of each of the oil dampers 3, 9, 13 and 17 is controlled by
The damping forces of 7, 11, and 15 are set to "soft state" (step S2).

On the other hand, the controller 25 determines in step S1 that the absolute value of the output of the differential
If the absolute value of the output of the differential amplifier 47 is equal to or greater than the absolute values of the first positive and negative thresholds of the “threshold group”, the positive and negative first thresholds of the “second threshold group” It is determined whether the threshold value is equal to or greater than the absolute value (step S
3).

The controller 25 determines that the absolute value of the output of the differential amplifier 47 is greater than or equal to the absolute values of the positive and negative first thresholds of the "first threshold group" and that the "second threshold group" If the absolute value of the second threshold value is smaller than the absolute value of the second threshold value (e.g., the vehicle traveling road surface is relatively flat and the crosswind is moderate), the operation of each actuator 5, 9, 13, 17 is controlled. Then, the damping force of each of the oil dampers 3, 7, 11, 15 is set to the "medium state" (step S4).

Next, the controller 25 controls the differential amplifier 4
It is determined whether or not the absolute value of the output of No. 7 has dropped below the absolute values of the positive and negative first thresholds of the “first threshold group” (step S5). Does not fall below the absolute values of the positive and negative first thresholds, the process returns to step S3, while the positive and negative first thresholds of the "first threshold group". When the value falls below the absolute value of each value, each of the actuators 5, 9, 13,
17 by controlling the operation of each oil damper 3, 7, 11, 1
After maintaining the damping force of No. 5 in the "medium state" for, for example, 2 seconds, the state is switched to the "soft state" (step S6).

On the other hand, the controller 25 determines in step S3 that the absolute value of the output of the differential
If the absolute values of the first and second threshold values of the threshold group are equal to or greater than the absolute values of the first and second threshold values (for example, when there is a rut on the road surface on which the vehicle is traveling and the crosswind is strong), each actuator 5, 9, 13, 17
To set the damping force of each of the oil dampers 3, 7, 11, and 15 to the "hard state" (step S7).

Next, the controller 25 controls the differential amplifier 4
It is determined whether or not the absolute value of the output of No. 7 has dropped below the absolute values of the positive and negative first thresholds of the “first threshold group” (step S8). Falls below the absolute value of the first positive and negative thresholds of
The operation of each of the actuators 5, 9, 13, 17 is controlled to reduce the damping force of each of the oil dampers 3, 7, 11, 15 by, for example, 2
After maintaining the "hard state" for two seconds, the state is switched to the "soft state" (step S9). The above is the flow of the suspension control in the present embodiment.

As described above, according to this embodiment, the voltage corresponding to the twist of the stabilizer 27 is detected by the first and second potentiometers 31 and 35 attached to the stabilizer 27, and the first voltage is detected by the differential amplifier 47. And the second
By detecting the potential difference between the detection voltages of the potentiometers 31 and 35, it is possible to grasp the torsion state of the stabilizer 27 (in other words, whether the left and right front wheels move in opposite phases in the vertical direction). It is possible to accurately detect a rolling phenomenon that acts on the vehicle body under the influence of a rut on a traveling road surface, a cross wind, or the like.

Further, according to the present embodiment, the output of the differential amplifier 47 which changes according to the magnitude of the rolling acting on the vehicle body, the "first threshold group" and the "second threshold group" Oil dampers 3, 7, 1 based on the size relationship of
Since the damping force of 1, 15 is switched to a preset damping force, the rolling acting on the vehicle body cannot be detected due to the influence of a rut or a cross wind on the road surface of the vehicle as in the prior art. It is no longer necessary to set a high damping force in advance at the expense of ride comfort to enhance
As a result, it is possible to achieve both steering stability and riding comfort during high-speed running.

Further, according to the present embodiment, the differential amplifier 47
When the absolute value of the output is less than the absolute value of the "first threshold value group" (when the vehicle traveling road surface is flat and the crosswind is weak)
Sets the damping force of each of the oil dampers 3, 7, 11, and 15 to the "soft state", and sets the "first threshold group"
When the absolute value is not less than the absolute value of the second threshold value group and the absolute value is less than the absolute value of the “second threshold group” (when the vehicle traveling road surface is relatively flat and the crosswind is moderate), the damping force is set to the “medium state”,
Thereafter, when the value falls below the absolute value of both thresholds of the "first threshold group", the damping force is maintained in the "medium state" for 2 seconds and then switched to the "soft state".
If the absolute value of the "second threshold group" is greater than
When the damping force is set to the “hard state”, and then falls below the absolute value of the “first threshold group” (when there is a rut on the road on which the vehicle is traveling and the crosswind is strong), the damping force is set to the “hard state” for 2 seconds. After switching to the `` soft state '' after maintaining the `` state '', the damping force can be set to the optimum state according to disturbance such as whether there is a rut on the vehicle traveling road surface or whether the cross wind is strong or weak. Therefore, it is possible to achieve both steering stability and riding comfort regardless of disturbance.

Further, according to the present embodiment, when the damping force of each of the oil dampers 3, 7, 11, 15 is returned from the "hard state" or "medium state" to the "soft state", the damping force is set to the "hard state". Since the holding time for holding the “state” or “medium state” for a predetermined time (for example, 2 seconds) is set, it is also possible to prevent a rolling phenomenon that acts on the vehicle body when returning the damping force.

In this case, in this embodiment, it is determined in the suspension control of FIG. 5 whether the vehicle speed is in the middle or low speed region or in the high speed region. When the vehicle speed is in the high speed region, it is shown in FIG. It is also possible to set the absolute values of the first and second threshold value groups to be lower to facilitate the suspension control of FIG. This makes it possible to further improve the steering stability during high-speed running of the vehicle.

In this embodiment, the case where the twist of the stabilizer is detected by the potentiometer has been described as an example. However, the present invention is not limited to the potentiometer, and the twist of the stabilizer is detected by, for example, a photo interrupter system or a variable inductor system. It is also possible.

In this embodiment, in steps S6 and S9 in FIG. 4, each of the oil dampers 3, 7, 11, 1
After controlling the damping force of No. 5 in the "medium state"("hardstate") for 2 seconds, the control was returned to the "soft state", but the time for maintaining the "hard state" was limited to 2 seconds. Instead, it can be set to an arbitrary time (a short time in seconds).

In this embodiment, the numerical values of the first and second threshold value groups for suspension control are set to the numerical values shown in FIG. 4, but the numerical values of the first and second threshold value groups are The values are not limited to those shown in FIG.

[0039]

As described above, according to the suspension control apparatus for a vehicle of the present invention, the twist on the right wheel side of the stabilizer is detected by the first detecting means, and the left wheel of the stabilizer is detected by the second detecting means. Side torsion, and a function to determine the magnitude relationship between the absolute value of the detected difference between each torsion and the absolute value of each reference value of the first and second threshold value groups. Based on the magnitude determination result, it is possible to determine the degree of rolling that acts on the vehicle due to disturbances such as a rut on the road surface on which the vehicle travels and crosswinds. The effect that it can be performed according to the degree can be produced.

Further, according to the vehicle suspension control apparatus of the present invention, the absolute value of the difference in twist between the right wheel side and the left wheel side of the stabilizer and the absolute value of each reference value of the first and second threshold value groups are determined. It has a function to set the damping force of the suspension mechanism to low / medium / high depending on the magnitude relationship with the value. Because it is not equipped with a function to detect rolling that acts on the vehicle, it is not necessary to set a high damping force in advance at the expense of riding comfort in order to enhance the steering stability during high-speed running of the vehicle. As a result, it is possible to improve the riding comfort particularly during high-speed running. Furthermore, in other words, the damping force can be set to an optimum state according to the degree of rolling caused by disturbance such as whether there is a rut on the vehicle traveling road surface or whether the cross wind is strong or weak. Regardless, it is possible to achieve an effect that it is possible to achieve both steering stability and ride comfort.

Further, in the vehicle suspension control device according to the present invention, the absolute value of the torsional difference is equal to or larger than the absolute value of any one of the reference values of the first threshold value group and the absolute value of the difference value of the second threshold value group. If the value falls below the absolute value of any of the reference values of the first threshold value group after the absolute value falls below the absolute value of any of the reference values, the damping force is maintained at a medium level for a predetermined period of time. Set to a lower state, and after the absolute value of the torsional difference is greater than or equal to the absolute value of one of the reference values of the second threshold group, the absolute value of one of the reference values of the first threshold group If the damping force is maintained at a higher level for a predetermined period of time when it falls below a certain value and then set to a lower level, the damping force is changed from a higher level or a medium level to a lower level. It is also possible to prevent the rolling phenomenon that acts on the car body when returning Made, there is an effect that.

[Brief description of the drawings]

FIG. 1 is a control block diagram illustrating a configuration of a main part of a vehicle according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a configuration of a main part of a vehicle in the embodiment.

FIG. 3 is an explanatory view showing a state where first and second potentiometers are attached to a stabilizer in the embodiment.

FIG. 4 is a diagram illustrating an output example of a differential amplifier according to the present embodiment.

FIG. 5 is a flowchart of suspension control in the embodiment.

[Explanation of symbols]

2,6,10,14 Suspension mechanism 3,7,11,15 Oil damper 4,4,8,12,16 Coil spring 5,9,13,17 Actuator 25 Actuator 25 Controller as control means 27 Stabilizer 31 First potentiometer as first detecting means 35 Second potentiometer as second detecting means 47 Differential amplifier 48 Memory as storage means

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B60G 17/015

Claims (2)

(57) [Claims] 1. A first detecting means attached to the stabilizer of a vehicle equipped with a suspension mechanism and a stabilizer and detecting a twist on the right wheel side of the stabilizer, and a first detecting means attached to the stabilizer of the vehicle and provided with the stabilizer. A second detecting means for detecting a twist on the left wheel side, and a set of first and second reference means having positive and negative reference values relating to a difference in torsion detected by the first and second detecting means, respectively.
And a set of second thresholds respectively set corresponding to each reference value of the first threshold group and having a value larger than each of the set reference values Storage means for storing a group, and control means for controlling the damping force of the suspension mechanism based on the detection data of the first and second detection means and the storage data of the storage means, the control means comprising: The magnitude relationship between the absolute value of the difference in torsion detected by the first and second detection means and the absolute value of each reference value of the first and second threshold value groups stored in the storage means is determined. When the absolute value of the torsional difference is less than the absolute value of any of the reference values of the first threshold group, the damping force of the suspension mechanism is set to a lower state; Of the twist difference If the paired value is equal to or greater than the absolute value of any of the reference values of the first threshold group and less than the absolute value of any of the reference values of the second threshold group, the damping force is set to the middle value. A damping force setting function that sets the damping force to a higher state when the absolute value of the torsional difference is greater than or equal to the absolute value of any of the reference values of the second threshold value group. A suspension control device for a vehicle, comprising: 2. The control unit according to claim 1, further comprising: an absolute value of the difference between the torsions is equal to or greater than an absolute value of one of the reference values of the first threshold value group, and If the value falls below the absolute value of any of the reference values of the first threshold value group after falling below the absolute value of any of the reference values, the damping force is maintained at a medium state for a predetermined time. After the absolute value of the torsion difference is equal to or greater than the absolute value of any one of the reference values of the second threshold value group, 2. A damping force setting function for holding the damping force at a higher level for a predetermined time and setting the damping force at a lower level when the value falls below the absolute value of the reference value. The vehicle suspension control device according to any one of the preceding claims.